Hydraulic gear shift mechanism

Abstract

A shift control device is described. The shift control device is attachable to the handlebar of a bicycle for controlling the piston of a hydraulic shift mechanism and includes a bracket attachable to the handlebar, a pivot shaft, a rotating member, and a control lever. The pivot shaft is spaced apart from the handlebar and fixedly secured to the bracket. The rotating member is rotatable in a first direction and a second direction about the pivot shaft. The control lever is operatively connected with the rotating member and biased in a neutral position.

1. A shift control device attachable to the handlebar of a bicycle for controlling the piston of a hydraulic shift mechanism, the shift control device comprising:
 a bracket attachable to the handlebar; 
 a pivot shaft spaced apart from the handlebar and fixedly secured to the bracket; 
 a rotating member rotatable in a first direction and a second direction about the pivot shaft, such that the rotation of the rotating member in the first direction moves the piston of the hydraulic shift mechanism in a push direction and the rotation of the rotating member in the second direction moves the piston of the hydraulic shift mechanism in a return direction; and 
 a control lever operatively connected with the rotating member and biased in a neutral position. 
 
   
   
     2. A shift control device, comprising:
 a bracket attachable to a handlebar; 
 a master piston; 
 a pivot shaft spaced apart from the handlebar and fixedly secured to the bracket; 
 a rotating member rotatable in a first direction and a second direction about the pivot shaft and operatively connected to the master piston, such that the rotation of the rotating member in the first direction moves the master piston in a push direction and the rotation of the rotating member in the second direction moves the master piston in a return direction; and 
 a control lever operatively connected with the rotating member and biased in a neutral position, wherein the neutral position is between the first and second directions. 
 
   
   
     3. The shift control device of  claim 2 , further comprising a master cylinder assembly, the master cylinder assembly including a master chamber having the master piston disposed therein and an adjuster chamber having an adjusting piston disposed therein. 
   
   
     4. The shift control device of  claim 3 , further comprising a slave cylinder assembly having a slave piston, wherein the master cylinder assembly is in fluid communication with the slave cylinder assembly. 
   
   
     5. The shift control device of  claim 4  wherein the slave piston has an initial position and the adjusting piston has a depth within the adjuster chamber which is adjustable to vary the initial position of the slave piston. 
   
   
     6. The shift control device of  claim 2  further comprising a push mechanism operatively connected to the rotating member and a return mechanism operatively connected to the rotating member, wherein the operation of the push mechanism rotates the rotating member in the first direction and the operation of the return mechanism rotates the rotating member in the second direction. 
   
   
     7. A method of shifting gears in a hydraulic gear shift mechanism for a bicycle having a master piston and a master cylinder, comprising the steps of:
 providing a shift control lever spaced apart from the handlebar, wherein the lever is biased in a neutral position and movable in a first direction and a second direction, and wherein the neutral position is between the first and second directions, wherein the hydraulic gear shift mechanism includes a rotating member rotatable about a pivot shaft and operatively connected to the master piston; 
 operating the lever in the first direction to rotate the rotating member and control the motion of the master piston in a push direction; 
 operating the lever in the second direction to rotate the rotating member and control the motion of the master piston in a return direction; and 
 wherein the control lever returns to the neutral position after operation. 
 
   
   
     8. The method of  claim 7  wherein the first direction is the direction from the neutral position toward the handlebar, and the second direction is the direction from the neutral position away from the handlebar. 
   
   
     9. The method of  claim 7 , further comprising the steps of providing a slave cylinder assembly in communication with the master cylinder assembly, wherein the slave cylinder assembly includes a slave piston.